1. Field of the Invention
The present invention relates to a flexible retention skirt which forms part of an electrode assembly at the distal end of a pacing lead and which serves to hold an electrode tip of the assembly in a desired position within a heart.
2. Description of the Prior Art
Heretofore, various structures have been proposed for maintaining an electrode tip of an electrode assembly at the distal end of a pacing lead in a desired position within a heart. For example, in U.S. Pat. No. 3,902,501, there is disclosed an endocardial electrode having a plurality of pliant tines which are held against the electrode body during insertion and which are released and allowed to spread out when the electrode tip is in a desired position within a heart.
Also, in U.S. Pat. No. 3,719,190, there is disclosed a heart stimulation electrode with a conical positioning parachute which, when the electrode is inserted in a vein, permits blood flow in the vein to draw the electrode through the vein into the heart so that the electrode may be used with an external power source for stimulating the heart. When sufficient tension is applied to the pacing lead, the parachute will eventually invert to permit withdrawal of the electrode but will not return to its original shape in a heart cavity once it is inverted.
As will be described in greater detail hereinafter, the flexible retention skirt of the present invention provides for stable positioning of an electrode at the tip of an electrode assembly at the distal end of a pacing lead in a heart chamber, e.g. the atrium, by having a formation which engages heart tissue to minimize sliding back of the electrode, while at the same time having separable sections or being in the form of a partial skirt which facilitates removal of the electrode assembly when it is desired to do so by pulling on the pacing lead causing each skirt section or partial skirt to fold back over itself on retraction of the pacing lead and which sections or partial skirt will return to their or its' original orientation when the skirt is in an open space in a heart chamber for repositioning of the assembly in the heart chamber.